feat(forms): set exportAs to form for all form related directives

modules/angular2/src/forms/directives/control_group_directive.ts

@@ -58,7 +58,8 @@ const controlGroupBinding = CONST_EXPR(
   selector: '[ng-control-group]',
   hostInjector: [controlGroupBinding],
   properties: ['name: ng-control-group'],
-  lifecycle: [onInit, onDestroy]
+  lifecycle: [onInit, onDestroy],
+  exportAs: 'form'
 })
 export class ControlGroupDirective extends ControlContainerDirective {
   _parent: ControlContainerDirective;

modules/angular2/src/forms/directives/control_name_directive.ts

@@ -60,7 +60,8 @@ const controlNameBinding =
   hostInjector: [controlNameBinding],
   properties: ['name: ng-control', 'model: ng-model'],
   events: ['ngModel'],
-  lifecycle: [onDestroy, onChange]
+  lifecycle: [onDestroy, onChange],
+  exportAs: 'form'
 })
 export class ControlNameDirective extends ControlDirective {
   _parent: ControlContainerDirective;

modules/angular2/src/forms/directives/form_control_directive.ts

@@ -49,7 +49,8 @@ const formControlBinding =
   hostInjector: [formControlBinding],
   properties: ['form: ng-form-control', 'model: ng-model'],
   events: ['ngModel'],
-  lifecycle: [onChange]
+  lifecycle: [onChange],
+  exportAs: 'form'
 })
 export class FormControlDirective extends ControlDirective {
   form: Control;

modules/angular2/src/forms/directives/form_model_directive.ts

@@ -63,7 +63,8 @@ const formDirectiveBinding = CONST_EXPR(
   hostListeners: {
     'submit': 'onSubmit()',
   },
-  events: ['ngSubmit']
+  events: ['ngSubmit'],
+  exportAs: 'form'
 })
 export class FormModelDirective extends ControlContainerDirective implements FormDirective {
   form: ControlGroup = null;

modules/angular2/src/forms/directives/ng_model_directive.ts

@@ -17,7 +17,8 @@ const formControlBinding =
   hostInjector: [formControlBinding],
   properties: ['model: ng-model'],
   events: ['ngModel'],
-  lifecycle: [onChange]
+  lifecycle: [onChange],
+  exportAs: 'form'
 })
 export class NgModelDirective extends ControlDirective {
   control: Control;

modules/angular2/src/forms/directives/template_driven_form_directive.ts

@@ -19,7 +19,8 @@ const formDirectiveBinding = CONST_EXPR(new Binding(
   hostListeners: {
     'submit': 'onSubmit()',
   },
-  events: ['ngSubmit']
+  events: ['ngSubmit'],
+  exportAs: 'form'
 })
 export class TemplateDrivenFormDirective extends ControlContainerDirective implements
     FormDirective {